fmt_double() may write up to 8 characters into its format_str[]
buffer, which however only has room for 7 characters.

This case could be triggered by a call to erts_printf_format() with
any floating-point format that also includes #, and + or a space,
which may be uncommon, but a nif or driver could issue it.

Sign character was not accounted for.

Ex:
float_to_list(-3.1265538967899625e+69, [{decimals,16}]).

Writing of crash dumps were done using unbuffered IO. This
is slow since many small writes are done.

Use a FILE* with an allocated buffer to obtain buffered IO.

I wrote a small test program that created 50000 binaries of 200 bytes
each and then created a crash dump. The crash dumping was an order of
magnitude faster with buffered IO than without.

Clear ethr_not_inited__ early (like on unix)
to not get assertion in ethr_tsd_key_create("stacklimit")

This behaviour has been seen when using docker together with --cpuset-cpus.

Improve accuracy of timeouts using a premature timeout then
return to sleep with a shorter timeout just before requested
timeout. This approach is only used on certain platforms where
we know it improves the accuracy of the timeouts, e.g. MacOS X.